Hi,
The code in that form also works for me, but just because the
exception is caught and never reported. If you rethrow any exceptions
from the catch blocks than you should get something like the
following:
Detected attempt to establish Parent2(3) as the parent of Parent1(1)/
Child1(2) but the entity identified by Parent1(1)/Child1(2) is already
a child of Parent1(1). A parent cannot be established or changed once
an object has been persisted.
org.datanucleus.exceptions.NucleusUserException: Detected attempt to
establish Parent2(3) as the parent of Parent1(1)/Child1(2) but the
entity identified by Parent1(1)/Child1(2) is already a child of Parent1
(1). A parent cannot be established or changed once an object has
been persisted.
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager.checkForParentSwitch
(DatastoreRelationFieldManager.java:214)
at org.datanucleus.store.appengine.DatastoreRelationFieldManager
$1.setObjectViaMapping(DatastoreRelationFieldManager.java:129)
at org.datanucleus.store.appengine.DatastoreRelationFieldManager
$1.apply(DatastoreRelationFieldManager.java:108)
at
org.datanucleus.store.appengine.DatastoreRelationFieldManager.storeRelations
(DatastoreRelationFieldManager.java:80)
at
org.datanucleus.store.appengine.DatastoreFieldManager.storeRelations
(DatastoreFieldManager.java:795)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertPostProcess
(DatastorePersistenceHandler.java:288)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObjects
(DatastorePersistenceHandler.java:241)
at
org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject
(DatastorePersistenceHandler.java:225)
at org.datanucleus.state.JDOStateManagerImpl.internalMakePersistent
(JDOStateManagerImpl.java:3185)
at org.datanucleus.state.JDOStateManagerImpl.makePersistent
(JDOStateManagerImpl.java:3161)
at org.datanucleus.ObjectManagerImpl.persistObjectInternal
(ObjectManagerImpl.java:1298)
at org.datanucleus.ObjectManagerImpl.persistObject
(ObjectManagerImpl.java:1175)
at org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent
(JDOPersistenceManager.java:669)
at org.datanucleus.jdo.JDOPersistenceManager.makePersistent
(JDOPersistenceManager.java:694)
at hu.mapro.gae.test.forum.TestForum.testMultiParent(TestForum.java:
44)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke
(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke
(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:59)
at org.junit.internal.runners.MethodRoadie.runTestMethod
(MethodRoadie.java:98)
at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:
79)
at
org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters
(MethodRoadie.java:87)
at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:
77)
at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:42)
at org.junit.internal.runners.JUnit4ClassRunner.invokeTestMethod
(JUnit4ClassRunner.java:88)
at org.junit.internal.runners.JUnit4ClassRunner.runMethods
(JUnit4ClassRunner.java:51)
at org.junit.internal.runners.JUnit4ClassRunner$1.run
(JUnit4ClassRunner.java:44)
at org.junit.internal.runners.ClassRoadie.runUnprotected
(ClassRoadie.java:27)
at org.junit.internal.runners.ClassRoadie.runProtected
(ClassRoadie.java:37)
at org.junit.internal.runners.JUnit4ClassRunner.run
(JUnit4ClassRunner.java:42)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run
(JUnit4TestReference.java:46)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run
(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests
(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests
(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run
(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main
(RemoteTestRunner.java:197)
The error message is self-explanatory. According to my knowledge it is
impossible for a single entity to have multiple parents, just as it is
impossible to change the parent of an entity (or any other part of its
primary key).
But you were talking about a "class" being in owned realationship with
two different classes, not an "entity". If I remove the comment from
the code above that creates a new child entity before assigning it to
the second parent instance then it is working as expected. Of course
they will be two different employee instances with different parents
(of different types).
Marton
On Sep 21, 4:49 pm, leszek <leszek.ptokar...@gmail.com> wrote:
> That's very interesting because it works for me:
>
> @PersistenceCapable(identityType = IdentityType.APPLICATION)
> public class Employee {
>
> @PrimaryKey
> @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
> private Key id;
>
> private String firstName;
>
> private String lastName;
>
> }
>
> @PersistenceCapable(identityType = IdentityType.APPLICATION)
> public class A (B) {
>
> public Long getId() {
> return id;
> }
>
> public void setId(Long id) {
> this.id = id;
> }
>
> public Employee getE() {
> return e;
> }
>
> public void setE(Employee e) {
> this.e = e;
> }
>
> @PrimaryKey
> @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
> private Long id;
>
> }
>
> ========================
> (regardless if transaction is used or not - simply makePersistent
> without transaction)
>
> PersistenceManager em = EMF.get().getPersistenceManager();
> Employee e = null;
> try {
> em.currentTransaction().begin();
> A a = new A();
> e = new Employee();
> a.setE(e);
> em.makePersistent(a);
> em.currentTransaction().commit();
> } catch (Exception ee) {
> em.currentTransaction().rollback();
> }
>
> try {
> em.currentTransaction().begin();
> B b = new B();
> // e = new Employee();
> b.setE(e);
> em.makePersistent(b);
> em.currentTransaction().commit();
> } catch (Exception ee) {
> em.currentTransaction().rollback();
> }
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